Liquid crystal display devices include liquid layers and backlight devices. The backlight device of a liquid crystal display device is a device using white light or a device configured to emit white light mixing three primary colors (e.g. red, green, and blue). A backlight having light sources of three colors is designed to vary a balance of luminance among three colors so as to adjust a white balance (i.e. a chromaticity of white spots) (see Patent Literature Document 1).
It is preferable for display devices, configured to display graphic images such as pictures and illustrations, to constantly maintain a desired luminance and a desired chromaticity, which are preferred by users, for a long time. To constantly maintain a desired chromaticity, it is necessary for display devices, which are applied to the above uses and which are equipped with backlights each having light sources of three colors, to drive the light sources so as to achieve a desired balance of luminance among the light sources of three colors.